Answer:
Yes it is.
Step-by-step explanation:
For a triangle to be a right angled triangle, it needs to verify the pythagoras theorem which is
h² = p² + b²
where h is the longest side.
So,
15² = 12² + 9²
225 = 144 + 81
225 = 225
which is true.
So the triangle is a right angled triangle.
